Jim Merritt was born on November 21, 1907 in Kelso, Desha County, Arkansas to James B. Merritt Sr. and Leanna White Merritt. His father died of a flu epidemic in 1918. He attended Kelso public schools in McGehee, Desha County, Arkansas and graduated from McGehee High School in 1927, valedictorian of his class. Merritt later graduated from Cumberland University School of Law in Lebanon, Tennessee in 1928 and passed the Arkansas Bar examination that same year. He returned to McGehee in 1928 to practice law and served several terms as city attorney. During his second term as city attorney, Merritt met Mildred Dishough, an elementary school teacher from McGehee, and in 1934 the two married. In 1935, Merritt established a law office in McGehee where he practiced law until 1942, when he joined the Air Force at the beginning of World War II. He served three and a half years with the 8th Air Force as a turret gunner and radio operator. He was stationed in England, France, and Africa.

In 1945, Jim returned to McGehee and continued his law practice. When Judge E.G. Hammock retired as Chancellor of Drew, Desha, Ashley, Bradley, and Chicot counties, Merritt was asked to finish the term and was reelected to the position in 1954, making him the first chancellor elected from Desha County. He served that position until 1971. In addition to being chancellor, Merritt also served as Chairman of the Democratic Central Committee and President of the State Judicial Council.

After a heart attack in 1971, Merritt retired from law and focused his attention on his real interest: the history of Desha County. He studied the topic extensively and published his research in the yearly publications for the Desha County Historical Society, of which he was the president. Merritt died in 1990. He was a member of many organizations and clubs including the American Bar Association, Arkansas Bar Association, Southeast Arkansas Legal Institute, the Arkansas Judicial Council, McGehee Chamber of Commerce, American Legion, and Veterans of Foreign Wars. He was also a 32nd degree Mason, a member of the Arkansas Consistory, the Sahara Shrine Temple in Pine Bluff, and the Southeast Arkansas Shrine Club. He had been a member of the First Methodist Church since 1928 and taught Sunday school from 1946 to 1990.